Electrically-vibrated screen



June 5, 1923.

T. J. STURTEVANT ELECTRICALLY VIBRATED SCREEN "'2 Sheets-Sheet 2 FiledApril 28. 1922 NM N R M M Y 5 o a g 2 M mm M N 2 0 N m M W T N WM mm.m6; 7 B N@ 2 .[ili wmmuli L QQ EN mm mm m? mm m mm mm Jill on. ll A lunrelated o,

ones vans a. srnn'rnvsnr, or ivnnnnsrnr night. COMPANY, or nearest,arassaorznsnrrs, A conrona'rron or MASSACHUSETTS, ASSIGNUR TO STUIWZLFELECTlEtICALLY-VEERATED SCREEN.

Application filed April 28, $22.

To all to from it may concern 7 Be it known that l, THOMAS J.Sutfn'rnvans, a citizen of the United States, residing at Wellesley, inthe county of Norfolk and State of Massachusetts, have invented anImprovement in Electrically Vibrated Screens, of which the followingdescription, in connection with the accompanying draw ings, is aspecification, like characters on the drawings representing like parts.

The invention to be hereinafter described relates to separators forgrading materials, and more particularly to separators employing one ormore screens.

In. order that the meshes of the screen clothing shall be kept open foretficient classification of the materials, it is necessary to providemeans for vibrating-the clothing. Various types of vibrating mechanismshave been employed, such, for example, as cams and eccentrics forshaking the screens, at" hammer devices for imparting blows to thescreen clothing.

These devices are liable to subject the clothing to severe strains-whichstretch the wires of the clothing so as to enlarge the meshes thereof,and thereby prevent uniform classification of the materials. Thesestrains "also tend to cause pockets or local sagging in the clothing,which interfere with proper classification. The severe and vigorousvibration of the clothing by such devices. causes the clothing to tierback and forth along the lines of juncture of the clothing with itssupporting frame, thereby weakening the Wires of the clothing andultimately rupturing the same, so as to necessitate substitution of newclothing therefor.

Une of the purposes of the present invention, therefore, is to providemeans for vibrating the screen clothing by causing rapid tremors orpulsations of the clothing throughout the area thereof, so that theclothin is in a continuous state of rapid agi tatiomhut withoutsubstantial amplitude of vibration. To accomplish this, electro-magneticvibrating mechanism is employed in circuit with a source of electricitywhich is of a character or so controlled that the electromagnetic forceis rapidly varied and the armature of the magnet is rapidly agitated orvibrated. The pulsations of the armatnroin turn are transmitted to thescreen, and the clothing of the latter is in a highly Serial 150.557,309.

vibrant state which etl'ectively prevents clogging of the meshes of theclothing, so that the meshes are always kept open for uniform, etiicientclassification of the materials.

Heretofore. electromagnetic devices have been employed for vibratingscreens, and usually the armature of the magnet is secured to th screen,so that the latter receives vibrations or pulsations corresponding tothose of the armature.

On the other hand, in accordance with the present invention, thearmature is not connected to the screen, but the screen is supported bythe armature independently of positive connection therewith, and theweight of the screen is yieldingly sustained by a spring means whichacts on the armature in opposition to the vibrant pull by the armafduccd by the pulsating current supiereto. The construction is such thaton is free "to floaton its vibrant support and without materiallydeadening the lively vibration produced by the electromagnet.

ilith the aforesaid and other purposes in view, the character of theinvention may be best understood by reference to the followingdescription of one good form thereof shown in the accompanying drawings,in which:

Fig. 1 is a vertical longitudinal section through a separator embodyingthe invention;

2 on an enlarged scale is a transverse section taken on line 2-2 of Fig.1; and

Fig. 3 on an enlarged scale is a section taken on line 3-3 of Fig. 1.

Referring to the drawings, the separator shown therein as one good formof the in vention, comprises a frame 1 supporting a casing in inclinedposition. This casin comprises a bottom 3, sides 5 and a cover havingits upper end connected to the body by hinges 9.

'1 o introduce materials to be graded into this casing, a feed box ll isprovided at the upper end of the casing and in communication therewith.The materials are introduced into the feed box at one end. thereofthrough a neck 13, and are conducted longitudinally of the feed icon bya screw conveyor 15 which may be driven by usual. well.

known means, unnecessary to show herein. The materials fed along thefeed box by the conveyor, flow over a distributing plate 17, held indifferent vertical positions by adjustin screws 19. The materials"flowing over 1: e distributor plate gravitate downward and are directedinto the upper end of the casing by a deflecting plate 21. The feed boxmay be provided with hinged doors 23 and 25 which enable ready access tothe parts therein.

A screen or screens may be mounted in the casing, and in the presentinstance, two screens are employed, one an upper or scalper screen, andthe other a'lower or fine screen.

The upper screen comprises screen clothing'27 which may be stretched ona frame having side members 29 connected by end members 31. Intermediatethe side members and extending longitudinally of the screen are members33 which may be suitabl secured to the screen clothing 27.

Tile upper screen, in the present instance, may be supported on hangerplates 35 secured to and depending from the casing cover. Secured to theopposite sides of the screen are inclined members 37 adapted to engagethe hanger plates 35 and prevent materials from escaping from the screeninto the spaces between the side edges of the screen and the hangerplates.

The lower screen, in the present instance 01 the invention, comprisesscreen clothing 39 which may be stretched on a frame of wood or othersuitable material. This frame has side members 41 connected by endmembers 4:3. Intermediate the side members t1 and extendinglongitudinally of the frame, are members 45 which may be suitablysecured to the screen clothin At opposite sides of the screen areincllned memers 17 adapted to'engage the sides of the casing and preventmaterials from escaping from the screen into the spaces between the sideedges of the screen and the sides of the casin Suitable means may beprovided for supporting the lower screen. To accomplish this, in thepresent instance, the lower portion of. the screen is so ported on apair of leaf springs as (Fig. 1 having their lower ends secured to feet51 mounted on the bottom of the casing. The upper ends of these leafsprings engage angle plates 53 secured to the side members 11, theconstruction being such that the lower portion of the screen isyieldably supported by the leaf springs 19, and the screen is preventedfrom sliding downward by engagement of the angle plates 53 with theupper ends of the leaf springs. The upper portion of "thelower screen issupported by electro-magnetic mechanism for vibrating the screen to bedescribed.

This electromagnetic vibrating mechainseam nism, in the present instanceof the invention, comprises an electro-magnet 55 having feet 57 securedto and depending from a channel 59 carried by U-shaped hangers 61secured to and depending from the bottom of the casing adjacent thesides of the latter.

The electro-magnet has a coil 63, and cooperating therewith is anarmature, in the present instance, in the form of a core 65 whichprojects downward into the coil, so that its lower end is spacedsomewhat from a stop core 67 The upper end of the armature core issecured by a bolt 69 to a sup port, in the present instance, in the formof a channel bar 71.

The support 71 is yieldingly sustained by upper portions 73 of coilsprings 7 5. Embracing these coil springs intermediate the ends thereof,are clamps 7 secured by bolts 79 to the channel 59 referred to. Each ofthese clamps comprises a fixed part 83 (Fig. 3) and a removable part 85secured to the fixed part by through bolts 87, said parts having helicalseats conforming to the convolutions of the spring. The construction issuch that on release of the through bolts 87, the coil springs may begiven a rotary motion to screw them up or down in the seats of theclamps, thereby to vary the effective lengths of the spring portions asdesired.

Projecting upward through the coil springs 75 are posts 89 having theirlower portions threaded to receive flanged collars 91 secured indifferent positions of adjustment by nuts 93, washers 95 beinginterposed between the collars and the nuts. The lower portions 97 ofthe coil springs are confined between the clamps 77 and the collars 91,and by adjustment of the nuts and collars, the tension of the lowerportions of the springs may be varied as desired.

The posts 89 project upward through the coil springs and through collars99 and nuts 100 respectively beneath and above the supporting bar 71,and threaded on said posts. The posts project thence upward throughholes in the bottom of the casing, and through collars 101 and sleeves103 mounted on the casing bottom. The upper ends of the posts aresecured by nuts 105 and 107 to a cross channel or support 109.

Mounted on the cross channel 109 adjacent the ends thereof, are plates111 riveted to said channel. Plates 113 rest freely-on the plates 111,and are secured to a transverse channel 115 beneath and secured to theside members 4.1 and the intermediate longitudinal members 45 of thelower screen frame. Sockets 117 are secured on the intermediate members45 and resting in the sockets 117 are short posts 118 which engageplates 119 secured to a transverse channel 120 beneath and secured tothe side members 29 and 111-- The construction is such that the upperlilt portions 7 3 of the coil springs and the posts 89' serve ieldinglyto support the lower screen, and through the short posts 118, sup portthe upper screen.

' The upper portions 73 of the coil springs are confined between theclamps 77 and the collars 99 which are secured to the supporting channel71, and since the core 65 of the electromagnet is connected to the chan'nel 71,-the upper portions of the coil springs will support the core inopposition to the pull thereon by the magnet.

The eleotro-magnet is in circuit with a source of electricity which isof a character or so controlled that the electro-magnetic force israpidly varied, and the armature core is rapidly agitated or vibrated.In the present instance, the magnet is connected by conductors 123 and125 with a source of alternating electric current which increases in apositive direction to a maximum value, falls to zero, and increases to amaximum negative value, the current frequency being such that the magnetcore receives a pulsating movement, but the changes in the direction ofthe current are so rapid that the sup porting channel 71 is pulled downagainst the upper portions 73 of the coil springs 7 5 continuously, butwith a rapidly varying force. The magnet and upper and lower springportions, therefore, place the support 71 in a highly vibrant state, butthe amplitude of vibration may be so small or minute that the channelsupport does not have substantial movement.

The vibrations or tremors of the'core and support 71, are transmitted bythe posts 89 to the cross channel 109', and from the latter to the lowerscreen resting freely thereon, and from the lower screen through theshort posts 118 to the upper screen. It will be noted that the lowerscreen plates 113 rest freely upon the cross channel plates 111, but areindependent of positive connection therewith. As a consequence, thelower screen may float upon the cross channel, and the plates 111pulsating or vibrating, produce a rapid succession of taps or hammerblows against the plates 113 secured to the under side of the lowerscreen. As a result, the longitudinal members of the lower screen areplaced in a highly vibrant condition, and the vibrations thereof aretransmitted to the clothing and distributed throughout the area thereof,so that all of the meshes of the clothing are maintained in opencondition for efiicient grading efieot.

The upper screen may be introduced into the casing when the cover is inopen position, by sliding the screen longitudinally inward along thehanger plates which depend from the cover. When the screen has been slidfully inward, the flange of the upper end member of the screen -framewill slide over a pair of leaf springs 127 mounted on the upper ends ofthe hanger plates. When the flange of the end member reaches the ends ofsaid leaf springs, it will drop downward and engage the ends of saidsprings, thereby preventing the screen from slidin downward when thecover has been close The lower portion of the upper screen may rest onleaf springs 129 mounted on the hanger plates. g

- The upper screen iswholly supported by the hanger plates when open,and while the cover is being rocked down toward its closed position. Asthe cover approaches its closed position, the transverse channel 120which is secured to the under side of the screen, and the plates 119,will be brought downward so that said plates will engage the short posts118. This will transfer the support for the upper portion of the upperscreen from the hanger plates to said posts, so that the latter will beeffective to transmit the tremors or vibration from the lower screen tothe upper screen.

As stated, the lower screen is mounted freely and floats on the crosschannel 109, so that it may be vibrated by said cross channel, but sincethe screen is separate from the cross channel, it is susceptible ofvibratory movements independent of and at a different rate from saidcross channel. Lateral movements of the screen in the direction of theplane thereof, ma be limited by engagement of the incline members 47with the sides of the casing. Lateral movement of the upper screen inthe direction of the plane thereof may be limited by enga' ement or. theinclined members 37 with the anger plates 35.

The upper portions of the coil springs 75 yie ldingly support the upperportions of both screens, and oppose downward pull by the armature ofthe magnet. The lower portions of the coil springs 75 work in oppositionto the upper portions of the springs, and enable the tension and efiectof the upper port-ions of the springs to be adjusted as required. It isdesirable that the core of the magnet shall have its lower end adjusteda predetermined distance from the upper end of the stop core, andadjustment of the coil springs enables the space between said cores tobe regulated as desired.

It will be noted that the axis of the core of the magnet is disposed inoblique position in order that it may vibrate transversely to the planesof the screens. Since the coil springs 75 are of strong construction andare securely gripped intermediate the ends thereof, the tendency is toprevent lateral flexion of the springs, and the latter there fore willso support the posts 89 and channel 71 as to relieve the core of themagnet from side pressure and friction.

The electromagnetic vibrating mechanism is located beneath the casingwhere it is out of the way and protected from the dust w th in thecasing, and it is readily accessible for purposes of inspection,adjustment and r pair.

Also, the screens are readily accessible. W hen the cover is raised, itwill carry the upper screen with it, thereby rendering easily visibleboth the upper screen and the lower screen. The upper screen, ifdesired, may be easily removed by pulling the same longitudinallyoutward from the hanger plates, and the lower screen may be easilyremoved if desired, by lifting the same from the supporting springsbeneath the lower end thereof, and from the cross channel be neath theupper end thereof.

By my invention, simple and efficient electro-magnetic means is providedfor placing the screen or screens in a highly vibrant condition, but thevibrations may be of small amplitude, so that there is not r0- nouncedflexion of the screen clothing a ong the lines of juncture with thesupporting frame therefor, and this vibration is accomplished withoutimparting blows directly to tile screen clothing. The construction issuch that the clothing is efficiently vibrated throughout. the areathereof, so as to maintain the meshes of the clothing in open condition,but the destructive effects of the vibration, on the clothing is reducedto a minimum.

lit will be understood that the invent-ion is not limited to thespecific embodiment shown, and that various deviations may be madetherefrom without departing from the spirit and scope of the appendedclaims.

What is claimed is 1. A separator for grading materials, comprising, incombination, a support, a screen resting on, but not connected to saidsupport, and electro-magnetic means for imparting vibrations of minuteamplitude to said support and through the support to the screen in adirection transverse to the plane of the screen the latter being free tovibrate on and relatively to said support.

2. A separator for grading materials, comprising, in combination, anelectro-magnet having an armature, means for energizing said magnet toproduce rapid pulsations of said armature, and a screen having a frameand screen clothing, said frame being separate from the magnet and itsarmature and adapted to receive the pulsations from said armature in adirection transverse to the plane of the screen, the frame of the latterbeing susceptible of vibratory movements independent of and at adifferent rate from said armature.

3. A separator for grading materials, comprising, in combination, ascreen having a frame and screen clothing, spring means supporting saidframe, and electric means for imparting vibrations of minute amplitudeto the screen frame, the being independent of said spring supportingmeans and electric means, that it may be susceptible of vibratorymovements independent of those produced by the electric means.

4:. A separator for grading materials, comprising, in combination, ascreen hav' ing a frame and screen clothing, a support for said frame,and electro-magnet means for imparting vibrations of minute amplitudethrough said support to the screen frame, the latter being unattached tosaid support and electro-magnetic means, so that said frame may besusceptible of vibratory movements independent of those produced by saidelectromagnetic means.

5. A'separator for grading materials, comprising, in combination, aplurality of screens, a support for one of said screens,electro-magnetic means for imparting vibrations to the support andthrough the latter to the screen sustained thereby, and means totransmit vibrations from the vibrated screen to another of the screens,said screens being susceptible of vibratory movements independent ofthose of the vibrating means.

6. A separator for grading materials, comprising, in combination, anelectromagnet having an armature, spring means sustaining said armature,a screen supported freely on said armature, and means for energizingsaid magnet to cause the armature to vibrate with rapid pulsations andimpart vibrations to said screen, the latter being free from said springmeans and susceptible of vibratory movements, independent of thevibrations of said armature and spring means.

7. A separator for grading materials, comprising, in combination, asupport, a screen resting on but separate from said support, and anelectro magnet having an armature connected to said support, said magnetbeing adapted to be energized by an alternating electric current,thereby rapidly to vibrate said support, and the screen resting thereon,the screen being susceptible of vibratory movements independent of saidsupport.

8. A separator for grading materials, comprising, in combination, anelectromagnet, an armature bar cooperating with said magnet, means toenergize the magnet to draw the armature bar toward the same withvarying force, a screen for grading mate rials supported on saidarmature bar, and a pair of springs at opposite sides of said magnetsupporting said armature bar and opposing movement of said armature bartoward said magnet.

9. A separator for grading materials, comprising, in combination, anelectromagnot having an armature, a screen supported freely on saidarmature, spring means for i ii .ing means cooperatin supporting saidarmature, means for vary- .ing the tension of said spring'means, and

means for energizin said magnet by an alternating current, t ereby tovibrate said armature between the screen and the spring means andtransmit vibration to the screen.

10. A separator for grading materials, comprising, in combination, anelectro-magnet having a core, a stop adjacent the lower end of the core,a support connected to said core, spring means tending to move saidsupport away from said magnet, adj ustwith said support to vary thedistance 0 said core from said stop, a screen mounted on said supportindependent of positive connection therewith, and means to energize saidmagnet with varying force, thereby to vibrate said support and thescreen mounted thereon.

11. A separator forgrading materials, comprising, in combination, anelectro-magnet having an armature, spring means supporting saidarmature, a screen freely supported by said armature, means to energizesaid magnet with varying force, thereby to vibrate the armature and thescreen supported thereon, a seal r screen above the firstnamed screen,an means to transmit vibrations from the latter to the scalper screen.

'12. A separator for grading materials, comprising, in combination, acasi prising a bod and a cover, hangers. epending from sai cover, ascalper screen adapted to be supported by said hangers, a lower screenbeneath the seal er screen, electromagnetic-means for v1 rating thelower screen, and means to lift the scalper screen from said hangers andimpart vibration COIII'.

thereto from the lower. screen when the cover is in closed position.

13. A separator for grading materials, comprising, in combination, ascreen, a support for the screen, and electrical means for impartingvibrations of minute amplitude through the support to the screen in adirection transverse to the plane of the latter, said screen resting onsa1d support but unattached thereto so that the screen may havevibratory movements on said support independent of those of saidsupport.

14. A separator for grading materials, comprising, in combination, ascreen havin a frame and screen clothing carried by sai frame, meanssupportin the frame and unattached thereto that the screen may move upand down relatively to the support, and electrical means for imparting arapid succession of vibratory movements to the supporting means, andthrough the latter to the screen frame.

15. A separator for grading materials, comprising, in combination, aninclined screen having a frame and screen clothing, means for supportingthe lower end ,of th frame, sprin means for supporting the upper end oft e frame, and electrical means cooperating with said s ring means forimparting vibrations to t e upper end of the frame, the latter beingunattached to the electrical means so that the frame may be susceptibleof vibratory movements independent of those produced by said electricalmeans.

In testimony whereof, I have signed my name to this s ecification.

TH MAS J. STURTEVANT.

